Calculation of Time and Credits

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Chapter 11: Imprisonment

Calculation of Time and Credits


18 U.S.C. § 3624(b) provides that “satisfactory behavior,” described as “exemplary compliance with institutional disciplinary regulations,” earns good time credit, which reduces a federal prisoner’s time in Bureau of Prisons (BOP) custody. Good time is counted at the end of each year that the prisoner is incarcerated, beginning at the end of their first year in prison. While the statute allows for up to 54 days of good time for each year of the imposed sentence, the BOP used to award good time credit based on the number of days the prisoners actually served and not the sentence imposed by the judge, resulting in a maximum of 47 days of credit per year. Families Against Mandatory Minimums has published a helpful guide explaining how the BOP actually calculated good credit.[1] However, the First Step Act of 2018 modified this to ensure that the total 54 days of credit are attainable. It was not until a final rule implementing the credit recalculation process was enacted in 2022 that this change actually went into effect.[2]

All inmates, other than those serving a life sentence, are eligible for good time credits. In addition, the rule amending the calculation of credit allowing for a total of 54 days of credit for each year of the sentence applies retroactively.

If the BOP determines that the prisoner has not complied with institutional regulations, they will either receive no credit or lesser credit (the appropriate amount of which is determined by the BOP). The statute also instructs the BOP to consider whether the prisoner is working toward a high school diploma or GED. Following the enactment of the Prison Litigation Reform Act (PLRA), only prisoners who have made satisfactory progress toward a high school diploma or GED are eligible for the maximum “54” days of good time credit.

[1] Families Against Mandatory Minimums. (2018). Frequently Asked Questions: Federal Good Time Credit. In FAMM.

[2] 87 FR 7938 (2022).


The First Step Act (FSA) provides that eligible inmates may earn FSA Time Credits (FTCs) for successfully participating and completing approved Evidence-Based Recidivism Reduction (EBRR) Programs or Productive Activities (PAs). The FSA allows qualifying inmates to apply FTCs toward prerelease community-based placement, such as RRCs or home confinement. It may also be applied toward early release to supervision.[3]

An EBRR Program is “a group or individual activity that has been shown by empirical evidence to reduce recidivism or is based on research indicating that it is likely to be effective in reducing recidivism; and is designed to help prisoners succeed in their communities upon release from prison.”[4] Such programs may include activities such as:

  • Social learning and communication, interpersonal, anti-bullying, rejection response, and other life skills
  • Family relationship building, structured parent-child interaction, and parenting skills
  • Classes on morals or ethics
  • Academic classes
  • Cognitive behavioral treatment
  • Mentoring
  • Substance abuse treatment
  • Vocational training
  • Faith-based classes or services
  • Civic engagement and reintegrative community services
  • Inmate work and employment opportunities
  • Victim impact classes or other restorative justice programs
  • Trauma counseling and trauma-informed support programs

A PA is “a group or individual activity that allows an inmate to remain productive and thereby maintain or work toward achieving a minimum or low risk of recidivating.”[5] PA groups, programs, classes, and individual activities include:

  • Structured, curriculum-based group programs and classes
  • Productive, free-time activities (e.g., recreation, hobby crafts, or religious services)
  • Family interactive activities (e.g., social visiting)
  • Personal growth and development classes (e.g., adult continuing education classes)
  • Institution work programs
  • Community service projects
  • Participation in an Inmate FInancial Responsibility plan

An updated list of approved EBRR programs and PAs is available here.

An inmate must be “successfully participating” in EBRR Programs or PAs to earn FSA Time Credits. Successful participation is determined by Bureau staff and is based on the inmate’s individualized risk and needs assessment. An inmate may also opt out and not earn status if they decline to participate in EBRR programs or PAs.

To determine whether or not an inmate is eligible, the unit team considers their current convictions and prior criminal convictions. For the current offense review, prisoners with a second or subsequent conviction under any of paragraphs (1) through (6) of § 2252A(a) (transportation, receipt, distribution, reproduction, or advertisement of child pornography) are ineligible to receive FTCs.[6] Prisoners convicted of any of paragraphs (1) through (3) of § 2252(a), (transportation, receipt, or distribution of material involving the sexual exploitation of minors) are ineligible.[7] Those convicted of § 2251 (production of child pornography) are ineligible.[8] If they are eligible based on their current offense, their prior adult convictions are reviewed. They are ineligible if they were sentenced to and served a term of imprisonment of more than a year for a federal or state offense consisting of murder, voluntary manslaughter, assault with intent to commit murder, aggravated sexual abuse and sexual abuse, abusive sexual contact, kidnapping, carjacking, arson, or terrorism.

Regardless of eligibility, all inmates receive a risk and need assessment to determine recommended EBRR programs or PAs.

For every thirty-day period that an eligible inmate has successfully participated in EBRR Programs or PAs recommended based on their risk and needs assessment, they will earn ten days of FSA Time Credits. They will earn an additional five days of FSA Time Credits if they are at a minimum or low risk for recidivating and have maintained a consistent minimum or low risk of recidivism over the most recent two consecutive risk and needs assessments conducted by the Bureau. Partial credit is not awarded.

An inmate may be unable to participate in EBRR programs or PAs and therefore unable to earn FTCs in circumstances including:

  • Placement in Disciplinary Segregation statuts
  • Designation status outside the institution
  • Placement in the custody of another jurisdiction
  • Placement in mental health/psychiatric holds
  • Detention as a material witness or for civil contempt
  • Placement in civil commitment
  • “Opting out” (Choosing not to participate)

An inmate may lose earned FTCs for violation of the requirements of the rules of an EBRR Program or PA. It is possible to appeal the loss of FSA credits.

[3] Federal Bureau of Prisons. (2023). First Step Act of 2018 – Time Credits: Procedures for Implementation of 18 U.S.C. § 3632(d)(4) (5410.01 CN-2). US. Department of Justice Federal Bureau of Prisons.

[4] Federal Bureau of Prisons. (2023). First Step Act of 2018 – Time Credits: Procedures for Implementation of 18 U.S.C. § 3632(d)(4) (5410.01 CN-2). US. Department of Justice Federal Bureau of Prisons.
[5] Federal Bureau of Prisons. (2023). First Step Act of 2018 – Time Credits: Procedures for Implementation of 18 U.S.C. § 3632(d)(4) (5410.01 CN-2). US. Department of Justice Federal Bureau of Prisons.

[6] § 3632 (d)(4)(D)(xxvii)

[7] § 3632 (d)(4)(D)(xxvi)

[8] § 3632 (d)(4)(D)(xxiv)


Enacted through the Violent Crime Control and Law Enforcement Act of 1994, 18 U.S.C. § 3621 directs the BOP to provide “residential substance abuse treatment (and make arrangements for appropriate aftercare) … for all eligible prisoners.” Those who complete the Residential Drug Abuse Program (RDAP) and who were convicted of “nonviolent” offenses may receive up to one year early release.[9] RDAP is “the only BOP program through which federal prisoners can earn a sentence reduction,” and “is one of the few avenues for mental health treatment available to inmates not suffering from acute psychological problems.”[10]

Inmates are eligible for RDAP participation if they have a substantiated diagnosis for a substance use disorder, were sentenced either under Chapter 227, Subchapter D for a nonviolent offense or under D.C. Code § 24-403.01 for a nonviolent offense, and successfully completed a RDAP.[11] However, the following categories of inmates are not eligible for early release:

  • Immigration and customs enforcement detainees
  • Pretrial inmates
  • Contractual boarders
  • Inmates with a prior felony or misdemeanor conviction for:
  • Homicide
  • Forcible rape
  • Robbery
  • Aggravated assault
  • Arson
  • Kidnaping
  • An offense that involves sexual abuse committed upon minors
  • Inmates with a current felony for a “crime of violence”:
  • An offense involving the use of physical force against another person or property
  • An offense involving a firearm or other dangerous weapons
  • An offense that presents serious potential risk of physical force against another
  • An offense that, by its nature or conduct, involves sexual abuse offenses committed upon minors
  • Those convicted of attempt or conspiracy to commit any of these types of offense
  • Inmates convicted of (b)(4) and/or (b)(5) of this section
  • Inmates who previously received an early release under 18 U.S.C. § 3621(e)

Therefore, those convicted of an offense under 2251 or 2251A (sexual exploitation of children / production of child pornography) are not eligible for a reduced sentence following RDAP completion. However, those with a conviction under 2252 or 2252A (non-contact child pornography offenses) may be eligible.[12] That being said, all sex offenders are eligible to participate in RDAP, even if they are not eligible for the resulting reduced sentence.

To have a substance use disorder, one’s drug or alcohol use must meet the definition of substance abuse or dependence in the Diagnostic and Statistical Menu of Mental Disorders. Attorneys can help those facing incarceration with properly documenting a substance use disorder so that they may participate in the RDAP. Substance abuse is typically documented in the Presentence Report (PSR). Letters from doctors, mental health professionals, treatment providers, parole or probation officers, social workers, or judges are helpful in demonstrating a “verifiable” substance use disorder.

Prisoners can either be referred by unit or drug treatment staff, or they can file a request with the Drug Abuse Program Coordinator (DAPC). The DAPC determines whether or not an inmate is qualified for participation in the RADP. The DAPC will typically complete a clinical interview of the prisoner to help determine their eligibility. If they have received a prior early release under § 3621(e), is a contract boarder, is a pretrial offender, has a detainer prohibiting the completion of the RDAP’s community treatment component, committed their federal offense before November 1, 1987, or committed their D.C. offense before August 5, 2000, they are ineligible. They must also have a documented and verifiable substance use disorder within the 12-month period before their arrest, and typically need at least 24 months left of their sentence in order to have enough time to complete the RDAP. If the prisoner has a cognitive or learning impairment, or does not speak the language in which the RDAP is conducted, they might be unable to participate. If they are eligible, the DAPC will initiate the process of assigning the inmate with § 3621(e) status. The inmate is not compelled to participate in the RADP and may decline. If they accept, the DAPC will assign their conditional early release date. It is also worth noting that there may be a long waitlist before an inmate can get a spot due to the popularity of the program. Priority is typically given to those who are closer to their release dates.

The early release time frame is based on the length of the inmate’s sentence:

  • Sentence Length
  • Early Release Time-Frame
  • 30 months or less
  • No more than 6 months
  • 31-36 months
  • No more than 9 months
  • 37 months or more
  • No more than 12 months

If their sentence length is changed, the early release time frame will be recalculated accordingly.

The RDAP consists of three parts. The unit-based component is a six to twelve month, 500-hour residential program in which inmates participate in drug abuse treatment program activities and prison work or educational programs. Then, they participate in follow-up services offered in the prison after their release. Finally, transitional drug abuse treatment (TDAT) lasts up to six months and occurs in a halfway house. The RADP is only completed after all three phases are finished.

Drug Abuse Program, Designation and Sentence Computation Center, Unit Team, Transitional Drug Abuse Treatment, and Community Corrections staff identify, monitor, and document an inmate’s eligibility for early release. If an inmate is removed from the program for bad behavior, they are required to wait from three to six months before reapplying to the program.

Not every prison has an RDAP. A current list of participating locations may be found here. If an inmate’s current prison does not have an RDAP, they may be able to transfer to one with the program, which may first require a security level reduction.

For those who do not meet RDAP admission criteria, there is a 12-24 week Non-Residential Drug Abuse Treatment (NR DAP) program. Graduates are paid $30 and wardens are encouraged to consider them for maximum pre-release (halfway house or home confinement) placement.[13]

[9] 18 U.S.C. § 3621(e)(2). The exact time of early release is up to the Director’s discretion.

[10] Ellis, A., & Henderson, J. M. (2019). Federal Prison Guidebook (Revision 5). James Publishing.

[11] Federal Bureau of Prisons. (2009). Early Release Procedures Under 18 U.S.C. § 3621(e). In Federal Bureau of Prisons (5331.02, CN-1). U.S. Department of Justice Federal Bureau of Prisons.

[12] Federal Bureau of Prisons. (2009). Program Statement P5162.05: Categorization of Offenses (P5162.05).

[13] Ellis, A., & Henderson, J. M. (2019). Federal Prison Guidebook (Revision 5). James Publishing.


The BOP contracts with residential reentry centers (RRCs), or “halfway houses,” to provide assistance to inmates who are nearing release. These houses “provide a safe, structured, supervised environment, as well as employment counseling, job placement, financial management assistance, and other programs and services.”[14] They also assist with substance abuse treatment and medical and mental health care. They aim to rebuild community ties and supervise ex-offenders’ activities during the readjustment phase.[15]

People may be placed in a halfway house to serve all or part of their sentence, or to live for a period of time after being released from federal prison. If a person lives in a state with strict sex offender living restrictions, a halfway house can be a good option in the latter scenario if they otherwise would not have housing upon their release. While technically 18 U.S.C. § 3621(b) allows for the BOP to place a prisoner in a halfway house for their entire sentence, this is uncommon in practice. In practice, the most time any prisoner can get in a halfway house is 12 months. The court may recommend halfway house placement, but the BOP is not required to follow the recommendation. However, a 2010 BOP memo recommends that prisoners be considered for at least three months in a halfway house.

An RRC referral recommendation can be made by the unit team approximately 17-19 months prior to an inmate’s release. To determine the suitability of such a living arrangement and the appropriate length of placement (up to 12 months), the following five factors are considered:[16]

  • The resources of the facility contemplated;
  • The nature and circumstances of the offense;
  • The history and characteristics of the prisoner;
  • Any statement by the court that imposed the sentence:
  • Concerning the purposes for which the sentence to imprisonment was determined to be warranted; or
  • Recommending a type of penal or correctional facility as appropriate; and
  • Any pertinent policy statement issued by the Sentencing Commission.

If the Warden approves the unit team’s recommendation, an appropriate RRC contractor will decide whether or not to accept the inmate for a placement. If accepted, the RRM works with the RRC contractor to determine the placement date and the inmate is informed of the final decision. Sex offenders may be eligible for halfway house placement.

Importantly, those assigned a “Sex Offender” Public Safety Factor are ineligible for halfway house placement. However, those convicted of possession of child pornography are permitted to go to halfway houses.

A directory of every RRC that the BOP has contracts with can be found here.

Prisoners placed in a halfway house are responsible for their own medical care and/or health insurance, as well as a fee equal to 25% of their gross income. However, Transitional Drug Abuse Treatment (TDAT) is available to all and required for those who completed the in-prison portion of the RDAP.[17]

Even when an inmate is eligible for residence in a halfway house, it is worth considering whether or not this is the best option for their individual circumstances. For example, a study found that sex offenders in “view their experiences in the transitional facility (TF) as contrary to the rehabilitative ideal, and some indicate that this type of programming has collateral consequences for reentry,” such as if they are required to register as a sex offender in the state of the TF.[18] Even if a person is recommended for placement in a halfway house, they are not required to be placed there. At the same time, houses can provide a secure residence and align with risk management strategies.

People may shorten their halfway house time by demonstrating that they are eligible to be placed on home confinement, which typically requires a home to go to, a job waiting for them, transportation to and from that job, and money to pay for the halfway house’s daily fee regardless of whether or not they stay there.

[15] Federal Bureau of Prisons. (1998). Program Statement: Community Corrections Center (CCC) Utilization and Transfer Procedure. In U.S. Department of Justice Federal Bureau of Prisons (7310.04).

[16] 18 U.S.C. § 3621

[17] Families Against Mandatory Minimums. (2012). Frequently Asked Questions About Federal Halfway Houses & Home Confinement.

[18] Kras, K. R., Pleggenkuhle, B., & Huebner, B. M. (2014). A new way of doing time on the outside. International Journal of Offender Therapy and Comparative Criminology, 60(5), 512–534.×14554194


Home confinement is a method for prisoners to serve their sentence from their own home. They are required to keep a curfew, pay for their own medical expenses or insurance, and a fee of 25% of their gross income. They may have work requirements, drug testing, or other programs, some of which may be at a prison facility. They may also be subject to electronic home monitoring. If a prisoner is found not where they are supposed to be, they will be subject to consequences.[19]

18 U.S.C. § 3624(c) states that all inmates are eligible for home confinement consideration at their six-month or 10 percent date. Criteria for home confinement includes:[20]

  • Appropriate release residence
  • No recent major disciplinary issues
  • Any medical or mental health needs that can be met in the community
  • Secured employment is not required for placement on home confinement.

The prisoner may be placed in home confinement for six months or 10% of the total term of imprisonment, whichever is less. Prisoners determined to be higher risk or who require more reentry services may receive little or no time in home confinement.

People may either be placed directly on home confinement or sent there from a halfway house. Lower-risk, minimum-security inmates who are not RDAP graduates and already have an approved home may be considered for direct placement on home confinement, or placed in a halfway house for two weeks or less and then transferred to home confinement. If one is sent there from a halfway house, the manager of the halfway house must approve placement on home confinement. They will consider whether the prisoner’s home has a working telephone, whether other adults in the home consent to the prisoner’s placement there, and whether the prisoner has a job (desirable, but not required).[21]

[19] Federal Bureau of Prisons. (2016b). Program Statement: Home Confinement (7320.01).

[20] U.S. Department of Justice, & R. Davis, B. (2013). Memorandum: Guidance for Home Confinement and Residential Reentry Center Placements.

[21] Families Against Mandatory Minimums. (2012). Frequently Asked Questions About Federal Halfway Houses & Home Confinement.


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